As is well known to those skilled in the art, a bi-fuel vehicle is used for fuel efficiency, economical efficiency of fuel, exhaust gas, and so on. For example, the bi-fuel vehicle may use both liquefied petroleum gas (LPG) and gasoline.
The bi-fuel vehicle may drive on either gasoline or LPG according to a driver's selection. When the bi-fuel vehicle drives on gasoline, it is referred to as a gasoline mode, while when the bi-fuel vehicle drives on LPG, it is referred to as an LPG mode. In addition, a bi-fuel vehicle may use both LPG and diesel, both gasoline and compressed natural gas (CNG), or both CNG and diesel.
In a case in which a bi-fuel vehicle uses both LPG and gasoline, liquefied LPG in a bombe is vaporized to be combusted in an engine, so a vaporizer is provided with the bi-fuel vehicle. The vaporizer typically reduces a pressure of the liquefied LPG from the bombe, vaporizes it in a gas state, and then supplies it to the engine.
The LPG may be generally injected in the engine by a liquefied petroleum gas injection (LPGi) method or a liquefied petroleum injection (LPI) method, the LPGI method and the LPI method are well known to a person of an ordinary skill in the art, and thus detailed description thereof will be omitted.
However, when internal pressure of the vaporizer of the bi-fuel vehicle is excessively increased or decreased due to an accident, a bad environment, and so on, the bi-fuel vehicle may become a safety hazard, therefore safety measures are required.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.